I wrote to Kennedy Space Center because they are the lead for "human exploration of space" and
asked for interior spacecraft shots. I have left her contact info included here so she can answer any more questions too. Here is their list of resources:
From: "MCARTHUR, CYNTHIA L. (JSC-AP)" <firstname.lastname@example.org>
To: 'Tom Nolan' <email@example.com>
There are several web sites for online images. We have been very successful using printer transparencies and having educators print the picture directly on the transparency for use with an
overhead projector. Here is a listing of sites:
There are also several sites that have technical drawings of spacecraft, if this information is needed.
Please let us know if you need additional inforamtion